Progress in climate-treaty negotiations has been blocked because the United States has pushed to abandon the Kyoto Protocol while placing blame on developing countries, said negotiators and analysts on the last day of the Tianjin meeting.

They say tension is rising as the US, which never ratified the Kyoto agreement, presses hard to change the nature of commitments made by developed and developing countries, with the Cancun climate summit only a month away.

China's chief climate negotiator, Su Wei, said attempts to thoroughly revamp the Kyoto Protocol have blocked any possible progress in the talks.

"During the past six days, some developed countries have kept silent on their mitigation plans after 2012, when the first commitment period of Kyoto Protocol expires," Su said.

The US has targeted China and other major developing countries for not accepting the same monitoring and verifying process as developed countries, although the United Nations Framework Convention on Climate Change clearly mandates that they are not subject to the same verification.

Many of the richer nations want to "jump ship" from Kyoto to a new protocol, said Martin Khor, the executive director of South Center, expressing his strong disappointment at the deadlock.

"They want the major developing countries to accept the same obligations on emission reductions, and this is an obvious deviation from the Bali Road Map," said Su, adding that such action is a retreat from previous consensus reached by all parties.

This is a tactful indirect way to actually abolish the existing protocol while avoiding blame, said Su.

"Rather than honoring their existing legal commitments, rich nations are immorally trying to shift the burden to developing countries and extract further concessions from them," said Meena Raman from Friends of the Earth.

The US wants to blame China for the failure of talks even though Washington made no substantial contributions to the negotiation progress, said Yang Ailun, a climate campaigner from Greenpeace.

"The US has no problem with China's mitigation efforts to be performed with a carbon-intensity target, but they want this pledge to be the same as theirs - to accept strict transparency evaluations.

"But that undermines the principle of common, but differentiated responsibilities," said Yang.